Electrostatic particle separating apparatus



April 11, 1961 B. H. VLIER, JR 2,979,158

ELECTROSTATIC PARTICLE SEPARATING APPARATUS Filed Oct. 17, 1958 2Sheets-Sheet 1 BM/A/E 1/1 lER, JR,

INVENTOR.

WHAN/V 8 MMA/V/GAL A/I'omeys for li i/kafi/ b A Ar/ A ril 11, 1961 B. H.VLIER, JR 2,979,158

ELECTROSTATIC PARTICLE SEPARATING AP1 ARATUS Filed Oct. 17, 1958- 2Sheets-Sheet 2 l6 /8 4 49 7 /8 9 2 2/ F g. 49 Q9 Z Z0 Z5 25 24 m 2 w 7 Z5 w i, 22 #T g. 4.

BAA/NE H l/Z/E/Z JR.

INVENTOR.

Unite States Patent ELECTROSTATIC PARTICLE SEPARATING APPARATUS BlaineH. Vlier, Jr., Compton, Calif., assignor of sixty percent to Gordon M.Genge & Company, Inc., Los Angeles, Calif., a corporation of CaliforniaFiled Oct. 17, 1958, Ser. No. 767,890

3 Claims. (Cl. 183-7) The present invention relates generally toelectrical precipitation apparatus, particularly of the electrostatictype, for removing dust, smoke, fumes, mist, pollen and other foreignparticles from gaseous fluids, such as air, and the like.

Heretofore, electrostatic preoipitators have been in the main ofponderous size and necessitating special constructions for installation.Such apparatus, due to the rather extremely high voltage required foroperation and installation requirements, have for the most part beenlimited to industrial applications. Moreover, these devices were noteconomically and physically designed in such a way that they could beadapted for use in the treatment of air in such volume as would enabletheir use in domestic and relatively small, limited, industrial spaces.

Having the foregoing in mind, it is one object of the present inventionto provide a precipitator of the above type, which is capable of beingeconomically embodied in a relatively small, self-contained, portableunit for domestic and industrial use, thereby avoiding the necessity ofespecially designed constructions for installation.

A further object is to provide a precipitator of the electrostatic type,wherein the electrodes are so proportioned and designed that thegeneration of ozone will be maintained at a comparatively low value.

It is also a further object of the herein described invention to providean electric precipitator which will operate efiiciently with respect toremoval of large as well as fine particles from the circulated air.

Another object is to provide a device of the above character wherein theparticle collector may be easily cleaned, or may be constructed as athrowaway structure.

Still another object is to provide a device for electrostaticallycleaning air in a space, which utilizes relatively high DC. potentialhaving a low ripple factor, thereby preventing undesirable backionization and reducing generation of ozone therein.

Still another object is to provide an electric precipi tator whichutilizes a small ionizing surface and a large, smooth collector surfaceso that all particles will be charged to the same sign at the ionizingelectrode and not recharged to opposite sign at the collector electrode.

Further objects of the invention will be brought out in the followingpart of the specification, wherein detailed description is for thepurpose of fully disclosing the invention without placing limitationsthereon.

Referring to the accompanying drawings, which are IQC 2 v the housingwall being cut away to show the internal arrangement of parts;

Fig. 4 is a transverse section through the apparatus, takensubstantially on line -4-4 of Fig. 3;

Fig. 5 is an enlarged fragmentaryv sectional view showing theinterrelationship between the ionizing electrode and the collectorelectrode, taken substantially on line 5-5 of Fig. 3; and i Fig. 6 is aschematic wiring diagram of the electrical circuitry and interconnectionof the component parts of the apparatus' Referring more specifically tothe drawings, for illustrative purposes, a portable precipitator unitembodying the features of the present invention is disclosed in Fig. 1as comprising a substantially rectangular casing or housing 10 which isarranged in this case with transversely extending Z-rails 11-11 whichpermit the apparatus to be suspended from wooden frame members 12, asshown in Fig. 2, which may comprise the ceiling joist of a room, ormembers forming a part of a supporting frame work. While the apparatusis shown as being adapted for mounting in an elevated position in a roomor other area, the housing may, if desired, be supported on the floor ofthe area.-

The housing ltl is o-f box-like construction, and is fitted with hingedend frames 13 and 14 positioned at the opposite ends of the housing,each of these end frames lacing provided with a grille or screening 15to permit passage of air or other gaseous fluid which is to becirculated through the apparatus.

Within the housing 10, as perhaps best shown in Figures 3 and 4, atubular honeycomb structure, as generally indicated by the numeral 16,is removably .mount ed adjacent to the end frame 14,-and arranged to bewithdrawn for replenishment or cleaning, when the hinged end 14 isopened. I

The structure 16 is composed of sheet material which is deformed so asto provide a plurality of parallel hexagonal tubes 17 which are securedtogether by any conventional means to provde the honeycomb structure andeffect a plurality of parallel tubular flow channels 18 respectivelythrough the tubes. At the periphery of the structure 16, suitable bafllefins 19 are provided between the tubes and the adjacent walls of thehousing, while baflle fins 20 are similarly provided between the tubesand other walls of the housing.

The tubes of'the structure 16 may be constructed of a light metallicsheet metal, such as aluminum; or the structure 16 may be provided as athrowaway unit with the tubes constructed of cardboard or other suitablematerial, in which case the interior surfaces of the tubes would belined with a metallic coating or foil. The tubes 17 may be constructedof cylindrical or other configuration. However, the hexagonal tube ispreferred since it naturally permits the tubes to be assembled into ahoneycomb construction so that a maximum flow channel area may beobtained in a minimum section of the housing.

Adjacent the innermost end of the structure 16, a pair of spaced straps2121 of insulating material are secured at their opposite ends in eachcase to the adjacent opposite walls of the housing by means of suitableangle brackets 22 to provide an insulating support for a wire gridstructure, as generally indicated at 23, this grid structure beingcomposed of 'a plurality of parallel members 24 which are secured andheld in parallel relation by means of transversely extending members 25which are welded or otherwise secured to the members 24. The gridstructure is secured to the straps 21 by means of appropriate clips 26.It will be observed that there are a similar number of members 24 andtube rows, and

that each of the members 24 extends along a row of tubes.

As shown in Fig. 5, the grid structure 23 supports a plurality of branchwires or conductors 27 which respectively extend into each of the tubes17. The conductor 27 is preferably made of a wire size of suflicientlylarge diameter that it will not have an ionizing effect when arelatively high voltage, as hereinafter described, is connected thereto.As shown, the branch conductor 2-7 is offset intermediate its ends toprovide. an inner leg portion 28 and an outer end portion 29, in eachcase, between which a relatively fine filamentary member 30, such as awire, may be strung. The filamentary member 30 makes electrical contactat the end thereof which is connected with the leg portion 29, while theother end of the member is insulated with respect to the leg portion 28by means of a suitable insulating covering 31 which is provided on themembers 24 and 25 of the grid structure, as well as the adjacent innerend portions of the conductors 27, including the leg portions 28. It isdesirable that the filamentary members shall be as small in diameter aspossible, consistent with sufiicient strength to prevent breakage, andfor this purpose wires of a diameter of the order of .008 inch have beenutilized. The filamentary member in each case is positioned so as toextend substantially axially of the tube 17 with which it is associated.The member 30 forms an ionizing electrode while theinner surface of thetube 17 provides a collector electrode, and these electrodes cooperatewhen connected with a proper high voltage source to produce asubstantially uniform electrostatic field throughout the length of eachflow channel within each of the tubes 17, as will hereinafter bediscussed in greater detail. By supporting the filamentary membersadjacent the innermost ends of the tube 17, these members do notinterfere with the removal of the honeycomb structure 16.

As shown in Figures 2 and 3, upper and lower rail members 32 and 33 aresecured to the adjacent walls of the housing 10, these rail membershaving an elongate groove 34 respectively formed in their confrontingedges for slidingly receiving opposite edge margins of a filter framestructure 35 which carries a filter panel '36 of close mesh metallicmaterial, such as aluminum. The filter frame structure may be insertedand removed through a suitable slot in the housing wall, which may benormally closed by a removable closure member 37. This arrangementpermits removal of the filter frame and the filter panel as a unit forcleaning and for replacement, when desired.

As shown primarily in Fig. 3, there is a compartment 38 formed withinthe housing between the mounting for the filter frame structure 35 andthe end frame 13 within which a device is mounted for providing amovement of air through the apparatus. For purposes of illustration,this device is shown as comprising an electric motor 39 which issuspended from a wall of the housing by a suit able supporting bracket40. This motor drives a multiblade fan 41 which is positioned in anopening 42 formed in a transversely supported bathe plate 43 positionedinwardly of the end frame 13. With the arrangement described above, itwill be apparent that operation of the fan 41 will cause a circulationof air to flow into the apparatus through the grille 15, through theflow channels 18, the filter panel 36, to the opening 4 2 and thence outthrough the grille 15 associated with the end frame 13.

The compartment 38 further provides space for mounting of the voltageconverting means whereby a domestic AC. electric potential is convertedinto a relatively high DC. potential having a low ripple factor to beutilized for creating an electrostatic field in the path of flow of theparticle, laden air, whereby the particles are removed.

.The potential converting device is generally indicated by numeral 43,Fig. 2. As shown in Fig. 6, the potential converting device comprises atransformer 4- having a primary winding 45 which connects with adomestic A.C. electric source 46 through a primary control switch 47 4and safety switches 48 and 49. The output side of the transformer isconnected from a secondary winding 50 to a voltage tripler rectifyingand filtering circuit as generally indicated by the numeral 51, whichconverts the alternating current into a DC. potential of the order of14,000 volts, no load, which is reduced under load conditions tosubstantially 10,000 volts in the apparatus of the present invention.Moreover, the rectifying and filtering circuit is designed to produce anoutput potential having a low ripple factor, e.g., 3-5%. The positiveside of the output potential is grounded, while the negative side isconnected with the ionizing electrode filamentary member 30, the circuitbeing completed through the collector electrode tube 17 which isgrounded. The safety switches 48 and 4-9, are shown in Fig. 3 as beingassociated with the hinged end frames 13 and 14 of the housing, and areso arranged that these end frames must be in closed position in order toenergize the transformer by closure of the main switch 47. With thesafety switches closed, closure of the main switch energizes the motor39 to start movement of air circulating through the ap paratus.Energization of the transformer is indicated by an indicating lamp 52connected across the primary winding 4-5 of the transformer, and thecircuit is shown as including a protective fuse 53.

In its broad concept, the present invention differs in a number ofrespects from previous approaches for devices and apparatus of thischaracter. Heretofore, it was considered essential to utilize anionizing electrode having sharp points or projections thereon, and inthe main the arrangements produced a nonuniform electrostatic field sothat in some embodiments the removed particles were merely arrested onthe surface of the collector, and due to the presence of peak voltages,there was a tendency for back ionization and production of undesirablequantities of ozone which made the previous arrangements unsuitable fordomestic installation.

According to the present invention, is has been determined that greaterefficiency may be obtained by utilizing a small ionizing electrodesurface in combination with a large collecting surface, and that byproperly proportioning the spacing between these surfaces it is possibleto increase the emeiency of the separation, particularly where theionizing voltage has a low ripple factor.

By utilization of a small wire of the order of .008 inch diameter, it ispossible to obtain a uniform or constant electrostatic field; and thatby the use of a potential having a low ripple factor, the peaks areavoided so that there will be no back ionization, and all the particlesin the fluid will be charged to the same sign at the ionizing electrodeand not recharged to opposite sign at the collector electrode.

It has been further determined that by connecting the negative side ofthe high potential to the ionizing electrode, it is possible to utilizelower potentials of the order of 10,000 volts, thus making the deviceavailable for domestic operation. While the use of negative potential onthe ionizing electrode produces greater ozone than in the case where theelectrode is made positive, this is readily overcome by the use of apotential having a low ripple factor which prevents back ionization.

In the device of the present invention, as described above, both thelarge particles and fine particles are efficiently removed. The largerparticles are rapidly deposited near the entrance to the tubes 17, whilethe tines tend to collect toward the rear end of the tubes. Due to thefact that the particles are held in the uniform electrostatic field fora longer period of time, the particles which are removed and depositedon the inner wall of the collector tubes are compacted rather thanmerely being arrested. These particles can only be removed by means of adetergent, or if the collector tube structure is made of the throw-awaytype, then, of course, it is only necessary to dispose of the collectorunit and replace it with a clean unit.

In the event that some of the fine particles may not have been collectedin the tubes, then these particles will be caught in the mesh of thefilter panel 36 where they will become entrained and de-ionized, sincethis filter is grounded the same as the collector electrode.

From the foregoing description, it is believed clearly apparent that theapparatus of the present invention accomplishes the indicated objectivesas stated above.

Various modifications may suggest themselves to those skilled in the artWithout departing from the spirit of my invention, and, hence, I do notwish to be restricted to the specific form shown or uses mentioned,except to the extent indicated in the appended claims.

I claim:

1. Electrical precipitator apparatus, comprising: a housing open for thefiow of particle laden fluid there through; a plurality of hexagonaltubular members having uninterrupted inner exposed surfaces and securedtogether to form a unitary honeycomb structure; an insulating supportcarried by the housing at one end of said honeycomb structure, saidhoneycomb structure being removably carried in said housing whereby saidstructure may be removed as a unit in a direction away from saidsupport; a plurality of support wires carried by said insulating supportand respectively extending axially into each of said tubular members andoffset from the axes thereof; a plurality of electrically interconnectedfilimentary members and each carried by a support Wire to extendlengthwise and centrally of a tubular member; a high D.C. potentialsource connected to said tubular members and said filimentary membersfor establishing an electrostatic field in each of said tubular members;and means for moving said particle laden fluid through said tubularmembers.

2. Electrical precipitator apparatus, comprising: a substantiallyrectangular housing having hinged grilled opposite ends; a collectorelectrode structure removably supported in said housing adjacent one ofsaid grilled ends, and being replenishable through said one of saidgrilled ends when in opened position, said electrode structure includingat least one tubular member forming an air flow channel; an ionizingelectrode structure in said housing including at least one insulatedsupport wire extending axially into said tubular member and offset fromthe axis thereof and one filamentary member carried by said support wireand extending centrally of said tubular member; means in said housingfor circulating air through said grilled ends and said tubular member;and means in said housing for converting a relatively low input A.C.potential into a relatively high low ripple D.C. output potentialconnected to said ionizing electrode and said collector electrode.

3. Electrical precipitator apparatus, comprising: a substantiallyrectangular housing having grilled opposite ends, a collector electrodestructure supported in said housing adjacent one of said grilled ends,said electrode structure including at least one tubular member formingan air flow channel having an uninterrupted inner surface; an ionizingelectrode structure in said housing including an insulated support wireextending axially into said tubular member and olfset from the axisthereof and an extremely small filamentary member carried by saidsupport and extending cent-rally of said tubular member; means in saidhousing for circulating air through said grilled ends and said tubularmember; and means in said housing for converting a relatively low inputA.C. potential into an output no load D.C. potential of the order of14,000 volts, said output potential having a positive grounded sideelectrically connected with said collector electrode and a negative sideconnected with said ionizing electrode.

References Cited in the file of this patent UNITED STATES PATENTS2,233,639 Pegg Mar. 4, 1941 2,422,564 Pegg June 17, 1947 2,443,780Wintermute June 22, 1948 2,476,247 MacKenzie July 12, 1949 2,650,672Barr et al. Sept. 1, 1953 2,672,207 Hedberg Mar. 16, 1954 FOREIGNPATENTS 682,588 Germany Oct. 18, 1939

